If your feeling brave try downloading UBUNTU. You could try that on a CD without even installing it, then if you like it, instal it, dual booting with Vista. I dont know what you use on your machine but you may find you can do everything you want on UBUNTU which is entirely free and very Stable.....and no viruses , trojans etc
I agree UBUNTU is awesome my 11year old daughter got one in a usb stick..even puppy linux